iphone – imageOrientation返回Up,但照片显示颠倒

概述我正在从iPad照片库中抓取一些照片.我在横向模式下拍了几张测试照片,左边是iPad主页按钮,右边是. 所以在我的应用程序中,由于某种原因,一些照片显示为颠倒.我检查了他们的imageOrientation属性,它们都是0(意思是它们是UIImageOrientationUp).这意味着我甚至不知道我需要旋转哪些照片. 发生了什么,我怎么知道哪些照片需要旋转？谢谢 UIImage有一个属性imag 我正在从iPad照片库中抓取一些照片.我在横向模式下拍了几张测试照片,左边是iPad主页按钮,右边是.

所以在我的应用程序中,由于某种原因,一些照片显示为颠倒.我检查了他们的imageOrIEntation属性,它们都是0(意思是它们是UIImageOrIEntationUp).这意味着我甚至不知道我需要旋转哪些照片.

发生了什么,我怎么知道哪些照片需要旋转？谢谢

解决方法 UIImage有一个属性imageOrIEntation,它指示UIImageVIEw和其他UIImage使用者旋转原始图像数据.这个标志很有可能被保存到上传的jpeg图像中的exif数据,但是用来查看它的程序并没有遵守该标志.

要在上传时旋转UIImage以正确显示,您可以使用如下类别：
在.h文件中

UIImagefixOrIEntation.h

@interface UIImage (fixOrIEntation)- (UIImage *)fixOrIEntation;@end

UIImagefixOrIEntation.m

@implementation UIImage (fixOrIEntation)- (UIImage *)fixOrIEntation {    // No-op if the orIEntation is already correct    if (self.imageOrIEntation == UIImageOrIEntationUp) return self;   // We need to calculate the proper transformation to make the image upright.   // We do it in 2 steps: Rotate if left/Right/Down,and then flip if Mirrored.  CGAffinetransform transform = CGAffinetransformIDentity;  switch (self.imageOrIEntation) {      case UIImageOrIEntationDown:      case UIImageOrIEntationDownMirrored:        transform = CGAffinetransformTranslate(transform,self.size.wIDth,self.size.height);         transform = CGAffinetransformRotate(transform,M_PI);          break;    case UIImageOrIEntationleft:    case UIImageOrIEntationleftMirrored:        transform = CGAffinetransformTranslate(transform,0);        transform = CGAffinetransformRotate(transform,M_PI_2);        break;    case UIImageOrIEntationRight:    case UIImageOrIEntationRightmirrored:        transform = CGAffinetransformTranslate(transform,self.size.height);        transform = CGAffinetransformRotate(transform,-M_PI_2);        break;}switch (self.imageOrIEntation) {    case UIImageOrIEntationUpMirrored:    case UIImageOrIEntationDownMirrored:        transform = CGAffinetransformTranslate(transform,0);        transform = CGAffinetransformScale(transform,-1,1);        break;    case UIImageOrIEntationleftMirrored:    case UIImageOrIEntationRightmirrored:        transform = CGAffinetransformTranslate(transform,self.size.height,1);        break;}// Now we draw the underlying CGImage into a new context,applying the transform// calculated above.CGContextRef ctx = CGBitmapContextCreate(NulL,CGImageGetBitsPerComponent(self.CGImage),CGImageGetcolorSpace(self.CGImage),CGImageGetBitmAPInfo(self.CGImage));CGContextConcatCTM(ctx,transform);switch (self.imageOrIEntation) {    case UIImageOrIEntationleft:    case UIImageOrIEntationleftMirrored:    case UIImageOrIEntationRight:    case UIImageOrIEntationRightmirrored:        // Grr...        CGContextDrawImage(ctx,CGRectMake(0,self.size.wIDth),self.CGImage);        break;    default:        CGContextDrawImage(ctx,self.size.height),self.CGImage);        break;}// And Now we just create a new UIImage from the drawing contextCGImageRef cgimg = CGBitmapContextCreateImage(ctx);UIImage *img = [UIImage imageWithCGImage:cgimg];CGContextRelease(ctx);CGImageRelease(cgimg);return img;}@end

并在捕获图像保存期间调用此函数或从库中选择图像.

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